Linus Pauling 미국 과학자

Linus Pauling, Linus Carl Pauling (미국 오레곤 주 포틀랜드, 11994 년 8 월 19 일, 캘리포니아 빅서) 사망, 미국의 이론 물리 화학자, 두 명의 비공유 노벨상을 수상한 유일한 사람이 된 Linus Carl Pauling. 그의 첫 상 (1954)은 화학 결합의 성질에 대한 연구와 분자 구조를 규명하는 데 사용되었다. 두 번째 (1962)는 핵무기 시험을 금지하려는 그의 노력을 인정했다.

초기 생활과 교육

Pauling은 세 자녀 중 첫 번째이자 약사 인 Herman Pauling과 약사의 딸인 Lucy Isabelle (Darling) Pauling의 유일한 아들이었습니다. 오리건 주 콘돈과 포틀랜드에서 조기 교육을받은 후, 그는 오리건 농업 대학 (현재 오레곤 주립 대학교)에 입학하여 나중에 아내가 될 Ava Helen Miller를 만났으며 화학 공학 요약에서 과학 학사 학위를 받았습니다 그는 캘리포니아 공과 대학 (Caltech)에 참석하여 Roscoe G. Dickinson이 X 선을 사용하여 결정의 구조를 결정하는 방법을 보여주었습니다. 그는 박사 학위를 받았다. 1925 년 그의 결정 구조 종이에서 나온 논문. National Research Fellow로 짧은 기간을 보낸 후 Guggenheim Fellowship에서 유럽의 양자 역학을 공부했습니다.그는 18 개월의 대부분을 독일 뮌헨의 Arnold Sommerfeld 's 이론 물리 연구소에서 보냈습니다.

분자 구조의 해명

박사 후 연구를 마친 후 Pauling은 1927 년 Caltech로 돌아 왔습니다. 그는 오랜 교육 및 연구 경력을 시작했습니다. 화학 구조 분석은 그의 과학적 작업의 중심 주제가되었습니다. 그는 X- 선 회절 기술을 사용하여 몇 가지 중요한 규산염 및 황화물 광물에서 원자의 3 차원 배열을 결정했습니다. 1930 년에 독일로 여행하는 동안 폴링은 전자 회절에 대해 배웠고 캘리포니아로 돌아 왔을 때 분자의 핵에서 전자를 산란시키는이 기술을 사용하여 중요한 물질의 구조를 결정했습니다. 이 구조적 지식은 전기 음성 스케일을 개발하는 데 도움이되었으며, 공유 결합에서 전자를 끌어 당기는 특정한 원자의 힘을 나타내는 숫자를 할당했습니다.

To complement the experimental tool that X-ray analysis provided for exploring molecular structure, Pauling turned to quantum mechanics as a theoretical tool. For example, he used quantum mechanics to determine the equivalent strength in each of the four bonds surrounding the carbon atom. He developed a valence bond theory in which he proposed that a molecule could be described by an intermediate structure that was a resonance combination (or hybrid) of other structures. His book The Nature of the Chemical Bond, and the Structure of Molecules and Crystals (1939) provided a unified summary of his vision of structural chemistry.

The arrival of the geneticist Thomas Hunt Morgan at Caltech in the late 1920s stimulated Pauling’s interest in biological molecules, and by the mid-1930s he was performing successful magnetic studies on the protein hemoglobin. He developed further interests in protein and, together with biochemist Alfred Mirsky, Pauling published a paper in 1936 on general protein structure. In this work the authors explained that protein molecules naturally coiled into specific configurations but became “denatured” (uncoiled) and assumed some random form once certain weak bonds were broken.

On one of his trips to visit Mirsky in New York, Pauling met Karl Landsteiner, the discoverer of blood types, who became his guide into the field of immunochemistry. Pauling was fascinated by the specificity of antibody-antigen reactions, and he later developed a theory that accounted for this specificity through a unique folding of the antibody’s polypeptide chain. World War II interrupted this theoretical work, and Pauling’s focus shifted to more practical problems, including the preparation of an artificial substitute for blood serum useful to wounded soldiers and an oxygen detector useful in submarines and airplanes. J. Robert Oppenheimer asked Pauling to head the chemistry section of the Manhattan Project, but his suffering from glomerulonephritis (inflammation of the glomerular region of the kidney) prevented him from accepting this offer. For his outstanding services during the war, Pauling was later awarded the Presidential Medal for Merit.

While collaborating on a report about postwar American science, Pauling became interested in the study of sickle-cell anemia. He perceived that the sickling of cells noted in this disease might be caused by a genetic mutation in the globin portion of the blood cell’s hemoglobin. In 1949 he and his coworkers published a paper identifying the particular defect in hemoglobin’s structure that was responsible for sickle-cell anemia, which thereby made this disorder the first “molecular disease” to be discovered. At that time, Pauling’s article on the periodic law appeared in the 14th edition of Encyclopædia.

While serving as a visiting professor at the University of Oxford in 1948, Pauling returned to a problem that had intrigued him in the late 1930s—the three-dimensional structure of proteins. By folding a paper on which he had drawn a chain of linked amino acids, he discovered a cylindrical coil-like configuration, later called the alpha helix. The most significant aspect of Pauling’s structure was its determination of the number of amino acids per turn of the helix. During this same period he became interested in deoxyribonucleic acid (DNA), and early in 1953 he and protein crystallographer Robert Corey published their version of DNA’s structure, three strands twisted around each other in ropelike fashion. Shortly thereafter James Watson and Francis Crick published DNA’s correct structure, a double helix. Pauling’s efforts to modify his postulated structure had been hampered by poor X-ray photographs of DNA and by his lack of understanding of this molecule’s wet and dry forms. In 1952 he failed to visit Rosalind Franklin, working in Maurice Wilkins’s laboratory at King’s College, London, and consequently did not see her X-ray pictures of DNA. Frankin’s pictures proved to be the linchpin in allowing Watson and Crick to elucidate the actual structure. Nevertheless, Pauling was awarded the 1954 Nobel Prize for Chemistry “for his research into the nature of the chemical bond and its application to the elucidation of the structure of complex substances.”